U.S. Pat. No. 5,750,657 to Edwardson et al. describes a completely novel method of preparing a fibrin sealant utilizing a fibrin monomer composition. Fibrin monomer, generated by pre-treatment of fibrinogen with a thrombin-like enzyme, is used in a nondynamic state. As it is applied to a patient in need thereof, the nondynamic conditions are reversed so that the monomer can polymerize to form a fibrin polymer which serves as a fibrin sealant.
One concern in applying a fibrin sealant has been fibrinolytic stability. It has been believed that fibrinolytic factors can prematurely break down a sealant clot so that desired effects are not provided. WO 93/05067 to Baxter International describes a sealant composition with greatly reduced plasminogen levels to help ensure better in vivo residence time or stability. The compositions of WO 93/05067 have preferably no more than 10 .mu.g/ml of plasminogen.
It is also believed that pre-delivery concentrations of fibrin or fibrinogen need to be high for an effective fibrin sealant. For example, Immuno's marketed Tissucol has approximately 70-100 mg/mil of fibrinogen, Behringwerke's Beriplast has approximately 65-115 mg/ml of fibrinogen, Kaketsuken's Bolheal has approximately 80 mg/ml of fibrinogen and the Baxter sealant is believed to contain approximately 100 mg/ml of fibrinogen.